It will most likely be overheating because the heatsinks are blocked with dust/lint/etc. I've had this problem with my previous Toshiba P30 laptop and had to take it into a service centre once a year to have it manually cleaned out. This would be your best bet.
I ended up getting a Toshiba L300 and it hasn't failed on me yet and it's a dirt cheap laptop in comparison with others (I do my DJ'ing on there) and you can grab a good deal from www.notebookcity.co.nz
(where I got it from). The only thing is that you cant play good games on it die to the inboard GPU.